Conventionally, there has been known beamforming which outputs the same signals from the multiple antennas, and also simultaneously controls the directions of the signals by adjusting the phase and the amplitude of the signals (refer to Japanese Laid-Open Patent Publication No. 2006-5436, for example).
When the same signals are to be output from the multiple antennas, the same signals are not always output. It is thus necessary to measure the signals output from the respective antennas, and, then, to measure errors among the signals.
For example, when two antennas: antenna A and antenna B, are used, following steps are required: (1) connecting the antenna A to a measuring device, and causing the measuring device to measure a signal output from the antenna A; (2) connecting the antenna B to the measuring device, and causing the measuring device to measure a signal output from the antenna B; and (3) comparing a result of the measurement of the signal output from the antenna A and a result of the measurement of the signal output from the antenna B with each other.
However, according to the above-described method, the switching of the connections, which includes connecting the antenna A to the measuring device, disconnecting the antenna A from the measuring device, and connecting the antenna B to the measuring device, takes time and effort.
It is an object of the present invention to simplify measurement of differences in outputs from multiple terminals.